Gantt View: Activate Dependencies and use Predecessors

When you activate Dependencies, your sheet has the following functionality:

• Changes in the start or end date on the predecessor immediately adjust the dates of its dependents.
• Changes in two of the Start Date, End Date, and Duration columns automatically calculate the third value.
• Start Date, End Date, Duration, and % Complete roll up to parent rows as summary calculations.
• Parent row values are read-only, as they’re calculated automatically based on values in the child rows. 
• You can highlight the critical path in the Gantt chart to visualize what drives the overall project duration.

Take into consideration that when you activate dependencies, you can't use formulas in the Start Date, End Date, Duration, % Complete, and Predecessors columns.

Activate or deactivate Dependencies

1. Right-click any column header in the Gantt chart and select Project Settings.
    
2. Select the Dependencies enabled checkbox.
   
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3. Select which columns to use as the Predecessor column and the Duration column.

   If you don't have columns set up for this, Smartsheet automatically creates the Predecessors and Duration columns.

4. Select OK.

To stop using dependencies and remove the automation from the sheet:

1. Right-click any column header in the Gantt chart and select Project Settings.
2. Uncheck the Dependencies enabled box.
3. Select OK.

Duration and Predecessors

When you enter a duration or predecessor value in a row, the Start Date and End Date populate automatically based on the working days schedule established in the Project Settings.

Duration

Duration is the amount of working time between the start and end dates. The system automatically calculates duration based on a start and end date, or you can manually enter it in the Duration column.

When calculated automatically, your duration is returned in days. For other units, enter Duration manually. 

You can use different formats, for example:

• Weeks: 2w
• Whole working days: 4d
• Partial working days: 3.5d
• Hours: 7h
• Minutes: 60m
• Seconds: 500s
• Milliseconds: 50000ms
• A combination of hours, minutes, seconds, and milliseconds: 4h 30m

A duration of zero creates a diamond shape on the Gantt chart, indicating a milestone: a significant event or checkpoint.

Elapsed time can be used in the Duration column to ignore nonworking time (including nonworking days and holidays). Lead with an e to indicate duration in elapsed time, for example: e3d, e5h.

Consider the following when working with the Duration column:

• Parent rows always reflect duration in partial working days.
• If your task takes longer than anticipated, you can increase the duration to extend the end date. This will also automatically extend the end dates of any dependent tasks. 
• When you provide a duration and a start date, the dependency functionality calculates the end date automatically by adding the number in the Duration cell to the start date, excluding any non-working days.
• If using partial working days, Smartsheet considers the length of working days when calculating the end date.
• You can manually schedule a task to start on a non-working day. When doing so, the start date is included in the duration, but subsequent nonworking days are excluded.

Predecessors

You can make a task dependent on another task by typing another row's number in its Predecessor column. The date of the dependent task automatically adjusts as the predecessor task dates change.

The task dependencies that you create drive the project's critical path. With task dependencies, Smartsheet determines the sequence of tasks that drive the duration of the overall project.

To define predecessors:

1. Find the row for which you want to create a predecessor.
2. In the Predecessor column, type the row number for the item that must occur first.

You can add multiple predecessors by entering the row numbers into the cell and separating them by a comma.

Due to the parent roll-up functionality, adding predecessors to a parent row in a hierarchy applies the predecessor to all of its child rows. This predecessor relationship prevents direct changes in the dates in child rows. To work around this, set predecessors at the lowest-level child rows whenever possible.

Consider the following:

• If a predecessor drives a task's start or end date, you can change it manually by clicking the cell and selecting a new date. Doing so overrides the association with the predecessor and removes the value from the row.
• If a parent row has a predecessor value listed, this dependency relationship drives the start dates for each child row. Removing the predecessor value on the parent row makes child rows editable for you to change dates manually.

Edit a predecessor relationship

By default, when you specify a predecessor, a Finish-to-Start relationship is established between items, but you can change that.

Use the Lag field to represent a period of inactivity or overlap between the predecessor and dependent.

For instance, entering 1d into the Lag field for a Finish-to-Start dependency causes the dependents to start a working day after its predecessor finishes.

To schedule the dependents to start before the predecessor finishes, use a negative number (for example, -1d) to create lead time.

1. Select Edit Predecessors, located at the right of any Predecessors cell in the column.
2. Select the relationship type:

• Finish-to-Start (FS): Start after the predecessor finishes.
• Finish-to-Finish (FF): Finish at the same time that the predecessor finishes.
• Start-to-Start (SS): Start at the same time that the predecessor starts.
• Start-to-Finish (SF): Finish before the predecessor starts.

3. Select a Lag time. You can enter weeks, whole working days, partial working days, hours, minutes, seconds, milliseconds, or a combination (in a similar fashion to the Duration examples).
4. Select OK.